Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 192137

Area Forecast Discussion
National Weather Service Goodland KS
237 PM MST Mon Feb 19 2018

.SHORT TERM...(This evening through Tuesday)
Issued at 236 PM MST Mon Feb 19 2018

Forecast problem will be snowfall amounts tonight. Light snow has
fallen most if not the entire day over the northwest half of the
forecast area. This is despite the saturated air mass being below
700 mb. Not only was there ice in the column at the bottom of the
sounding according to the upstream 12z soundings but the dendritic
zone is at or near the surface. So the minor weak lift we have
received all day has allowed light snow or flurries to occur.
Accumulations so far have been near a half or below. The main change
for this air mass during the night will be for it to move over the
southern portion of the area and deepen over the remainder of the
area, especially in the northwest portion.

For tonight...Models are showing elevated Cape during the evening
over the western half of the area. But would not be surprised to
see this moving into the east overnight. I say that because
negative low and mid level theta-e lapse rates stay over the
western half of the area through the evening and then slowly
transition east through the rest of the night. So felt confident
to add isolated thunder to most of the area into the overnight

Right rear quadrant of upper jet starts affecting the northwest half
of the area during the mid and late evening. That area moves very
little during the night. Also strong mid level trough/baroclinic
zone and frontogenetic forcing follow this same path. High
resolution guidance has been very consistent through the day in
producing some bands of higher intensity snowfall near or over the
northwest corner. After running through all the parameters, I came
up with 3 to 5 inches of snow in the northwest corner, Yuma and
Dundy counties, for tonight. So went ahead and have hoisted a Winter
Weather Advisory for the night. The winds will be strong enough
enough that some patchy blowing snow will be possible, even a little
outside the area. Evening shift will have to watch if higher
snowfall amounts and the advisory need to be changed.

Also something else to watch for. Current forecast shows wind chills
dropping into the 10 to 15 below zero range in the northwest corner
as well.

For Tuesday...Above mentioned wind chills are in the northwest
corner during the morning. The mid level trough line stays to the
west the entire day. Models continue mid level lift and favorable
theta-e lapse rates over the area with the deepest moisture profile
over the northwest half. Baroclinic zone at 700 mb also remains over
the area. Above mentioned upper jet moves very little during the day
and is still affecting the southeast half of my area by the end of
the afternoon. Am thinking the models are ending snowfall to soon
and light snow or flurries could continue the entire day. Night
shift will have to look to see if this needs to be expanded or

Cloud cover, snowfall, snow cover, and an arctic air mass will keep
things cold with expected high temperatures near or below the
guidance blend.

.LONG TERM...(Wednesday through Sunday)
Issued at 330 AM MST Mon Feb 19 2018

Wednesday to Friday: A Canadian airmass extending southward into
the region Wed/Wed night will shift eastward to the Great Lakes
Thu/Thu night as cyclonic flow /troughing/ aloft becomes more
pronounced over the Intermountain West and a lee cyclone develops
in E/SE Colorado. With the above in mind, expect cold temperatures
lingering Wed/Wed night followed by a warming trend on Thu and Fri.

Light precipitation cannot be ruled out at times Thu-Fri, presumably
in assoc/w episodic warm advection and shallow frontogenesis (on
the N/NE periphery of a waxing/waning lee cyclone) modulated by a
series of small amplitude shortwaves ejecting northeast from the
Desert Southwest into the High Plains. With such a pattern,
confidence is very low with regard to whether or not light
precipitation will develop in eastern Colorado and western KS, let
alone timing, p-type, or

Friday night to Sunday: The west CONUS trough is expected to
become progressive Fri night into Sat as potent shortwave energy
digs southeast ashore the Pacific coast. Guidance suggests that this
feature will de-amplify as it traverses the Rockies and progresses
into the Central Plains early Saturday. Some potential for light
precipitation will exist as this feature progresses east of the
Rockies across portions of the Southern/Central Plains Fri night
and Sat, however, confidence is low given the increasingly
complex/progressive synoptic pattern evolving over North America
this weekend.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1032 AM MST Mon Feb 19 2018

For Kgld, mvfr conditions are expected through 06z tonight. At
that time ifr conditions will develop and continue until 15z
Tuesday morning vfr conditions should return. The winds will start
out from the northeast near 12 knots then shift to the east in the
afternoon. From 00z to 04z the winds will be east at 15 knots with
gusts to near 25 knots. From 04z tonight until 15z tomorrow, the
winds will be northeast near 13 knots. At 15z the winds will shift
to the north at 12 knots.

For Kmck, mvfr conditions with northeast winds near 12 knots are
expected until 06z. At that time mvfr conditions will still remain
but the winds will be from the north near 13 knots. At 14z, the
north winds near 13 knots will continue as vfr conditions should


CO...Winter Weather Advisory until 5 AM MST Tuesday for COZ090.
NE...Winter Weather Advisory until 5 AM MST Tuesday for NEZ079.



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